Re: [PATCH v5 1/4] cgroup: implement eventfd-based generic API for notifications

[Paul Menage <menage@google.com>]

On Thu, Jan 7, 2010 at 4:55 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
>
> Use multi labels is much better:

I disagree with that - in the absence of a language that can do proper
destructor-based cleanup (i.e. a strictly controlled subset of C++ :-)
) I think it's clearer to have a single failure path where you can
clean up anything that needs to be cleaned up, without excessive
dependencies on exactly when the failure occurred. Changes then become
less error-prone.

Paul

>
> label4::
>        fput(cfile);
> label3:
>        eventfd_ctx_put(event->eventfd);
> label2:
>        fput(efile);
> label1:
>        kfree(event);
>
> compared to:
>
> +fail:
> +       if (!IS_ERR(cfile))
> +               fput(cfile);
> +
> +       if (event && event->eventfd && !IS_ERR(event->eventfd))
> +               eventfd_ctx_put(event->eventfd);
> +
> +       if (!IS_ERR(efile))
> +               fput(efile);
> +
> +       kfree(event);
>
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